数据库参数文件:inc.jsp
<%@ page import="java.sql.Connection"%>
<%@ page import="java.sql.DriverManager"%>
<%@ page import="java.sql.Statement"%>
<%@ page import="java.sql.ResultSet"%>
<%@ page import="java.sql.ResultSetMetaData"%>
<%
String drv = "org.gjt.mm.mysql.Driver";
String url = "jdbc:mysql://localhost:3306/demo";
String usr = "root";
String pwd = "mysql";
%>
测试文件:testjdbc.jsp
<%@page language="java" contentType="text/html;charset=gb2312"%>
<%@ include file="inc.jsp"%>
<%String sql = "select * from user";
try {
Class.forName(drv).newInstance();
Connection conn = DriverManager.getConnection(url, usr, pwd);
Statement stm = conn.createStatement();
ResultSet rs = stm.executeQuery(sql);
ResultSetMetaData rsmd = rs.getMetaData();
int cols = rsmd.getColumnCount();
while (rs.next()) {
for (int i = 1; i <= cols; i++) {
String field = (String) (rsmd.getColumnName(i));
String value = (String) (rs.getString(i));
out.print(field + "=" + value + ";");
}
}
rs.close();
stm.close();
conn.close();
} catch (Exception e) {
e.printStackTrace();
out.println(e);
%>
在Eclipse里报空指针异常
<%@ page import="java.sql.Connection"%>
<%@ page import="java.sql.DriverManager"%>
<%@ page import="java.sql.Statement"%>
<%@ page import="java.sql.ResultSet"%>
<%@ page import="java.sql.ResultSetMetaData"%>
<%
String drv = "org.gjt.mm.mysql.Driver";
String url = "jdbc:mysql://localhost:3306/demo";
String usr = "root";
String pwd = "mysql";
%>
测试文件:testjdbc.jsp
<%@page language="java" contentType="text/html;charset=gb2312"%>
<%@ include file="inc.jsp"%>
<%String sql = "select * from user";
try {
Class.forName(drv).newInstance();
Connection conn = DriverManager.getConnection(url, usr, pwd);
Statement stm = conn.createStatement();
ResultSet rs = stm.executeQuery(sql);
ResultSetMetaData rsmd = rs.getMetaData();
int cols = rsmd.getColumnCount();
while (rs.next()) {
for (int i = 1; i <= cols; i++) {
String field = (String) (rsmd.getColumnName(i));
String value = (String) (rs.getString(i));
out.print(field + "=" + value + ";");
}
}
rs.close();
stm.close();
conn.close();
} catch (Exception e) {
e.printStackTrace();
out.println(e);
%>
在Eclipse里报空指针异常
解决方案 »
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